1. Field of the Invention
Lubricating oil additives are prepared by reacting a dispersant composition containing at least one primary or secondary amino group with SO.sub.2.
2. Description of the Prior Art
Most commercial lubricating oils now contain dispersant additives to help keep the engine clean by dispersing sludge and varnish-forming deposits in the oil. Many of these additives contain nitrogen. Many recently developed additives combine dispersant activity with viscosity index improving characteristics. Additives which function in this manner are variously known in the art as detergent additives or dispersant additives. For the purposes of this description, the term "dispersant" is intended to include both dispersant and detergent additives.
U.S. Pat. No. 3,741,998 teaches the preparation of aqueous detergents via a two-stage process which comprises: (1) forming an adduct of sulfur dioxide or sulfur trioxide and a quaternary amine; and (2) reacting this adduct with an aziridinyl compound.
U.S. Pat. No. 3,843,722 teaches the preparation of alkyl amidosulfinic acid (bis-alkylamine) salts, useful as analytical reagents, by reacting an amine containing 1-20 carbon atoms with SO.sub.2.